1. Field of the Invention
The present invention relates to a recording material supplied for ink jet printing using liquid inks such as an aqueous ink (using dyes and pigments as colorants) and oil-based ink, and solid inks that are solids at room temperature and are used for printing by melting and liquefying the ink. Particularly, the invention relates to an ink jet recording sheet being excellent in ink receptivity with little blurring over time in image portions and being excellent in light fastness.
2. Description of the Related Art
Accompanying rapid progress of information technology industries in recent years, various information processing systems have been developed, and recording methods and recording apparatus suitable for the information processing systems also have been developed and made practical.
Among these recording methods, ink jet recording methods have come to be widely used for office as well as home use because of their advantages of printability property on various kinds of recording materials, relatively low-cost hardware and compact size, and excellent quietness.
Since resolution of the ink jet printer has increased in recent years, obtaining “photorealistic” high quality outputs has became possible, and various kinds of ink jet recording sheets have been developed with such improvement of hardware (printers).
Required characteristics for these ink jet printing sheets are generally: (1) rapid drying (rapid ink-absorption speed), (2) proper and uniform diameter of ink dots (no blurring), (3) good granularity, (4) high circularity of dots, (5) high color density, (6) high chroma (free of dullness), (7) good water resistance, light fastness and ozone resistance of printed portions, (8) high brightness of recording sheets, (9) good preservability of recording sheets (no yellow coloring or blurring of images in a long term preservation (excellent in prevention of blurring over time)), (10) substantially no deformation with good dimensional stability (sufficiently small curling), and (11) good runnability of hardware.
In the usage of photographic glossy paper sheets used for obtaining photorealistic high quality printed material, in addition to the carious aforementioned characteristics, the recording sheets are also required to have glossiness, glossiness of printed portions, surface smoothness and texture of printed paper sheets resembling that of silver salt photographs.
For improving the characteristics described above, ink jet recording sheets having a porous structure in the colorant receiving layer have been developed and made practical in recent years. Such ink jet recording sheets are endowed with excellent ink receptivity (rapidly drying property) and high glossiness by having the porous structure.
For example, Japanese Patent Application Laid-Open (JP-A) Nos. 10-119423 and 10-217601 have proposed ink jet recording sheets comprising fine inorganic pigment particles and a water soluble resin, wherein a colorant receiving layer having a high void ratio is provided on a substrate.
These recording sheets, particularly the ink jet recording sheet having the colorant receiving layer comprising the porous structure using silica as the inorganic pigment particles, are, because of their structure, excellent in ink absorbing properties while having high ink receptivity and high glossiness that enable high resolution images to be formed.
However, since these sheets have high oxygen permeability due to their porous coated layers, deterioration of components involved in the colorant receiving layer may be enhanced. Furthermore, the images may blur over time (referred to as time-dependent blurring hereinafter) as water is adsorbed on the silica surface.
In contrast, an ink jet recording material using cationic resins has been proposed for preventing time-dependent blurring from occurring (JP-A Nos. 2001-26179 and 11-78221). However, these recording materials have not possessed the porous structure using fine particles.
Recording materials having colorant receiving layers comprising the porous structure using fine particles are described in JP-A Nos. 10-217601, 63-115780, 11-321079 and 11-328409. However, the cationic resins used in these publications are not always satisfactory for preventing time-dependent blurring from occurring.